Power-supply system



F. c. BAR-TON 1,774,467

POWER SUPPLY SYS TEM Filed Feb. 13, 1926 fLgJ.

Inventor-z Frederick C. Barton,

Hts Attorneg.

Patented Aug. 26, 193i) i STA Parser ERIC COMPANY, A CQRPORATION OF NEW YGRK rowan-sunny sirsrnar Application filed February 13,1926. Serial u 88,161.

My invention relates to power supply systems, and has for its principal object the provision of an improved system that is adapted to supply considerable amount of power from an alternating current source for the operation of a radio receiving set and a sound producing device such as a loud speaker or the like.

In supplying currents of audio frequency to a sound producing device, it is customary to amplify these currents by means of a power supply system comprising a plurality of thermionic amplifiers each provided with a cathode and anode. It is desirable that the current for operating a system of this charact r be supplied from a single source such as a house lightingcircuit. If the current for operating the system is supplied from an alternating current source, it mustbe rectified and filtered before it is supplied to the anode and cathode heating circuits of the amplifiers. plish this result by means of a single rectifier through which the alternating circuit is connected to the anode and cathode heating circults. Ihe use of a single rectifier in this mannenhowever, lnvolves the drfficultythat fluctuations in therectified current which are produced by variation in the audio frequency.

currents are liable to change the cathode heating current in a manner to produce distortion of the audio frequency signals.

In accordance with my invention, this difficulty is avoided by supplying the'anode circuits and cathode heating currents of the amplifiers throu 'h rectifiers whichoperate independently of one another.

My invention will be better understood from the following descriptionwhen considered in connection with the accmnpanying drawings and its scope will be pointed out in the appended claims.

Referring to the drawings, Fig. 1 shows an amplifying system wherein my invention has been embodied; and Fig. 2 shows the system as modified in certain respects to adapt it to a type of sound producing device dilferent from that shown by Fig. 1.

Fig. 1 shows a sound producing device 1 which is connected to current supply means it has been proposed to acccmshown as a transformer 2 through an amplifying system comprising a thermionic amplifier 3, a multistage amplifying and detecting apparatus at including a plurality of thermi onic devices 5 to 11 each provided with a 5 cathode and anode, a rectifier 19 through which current is supplied to the anode cir cuits of the thermionic amplifier 3 and the apparatus l, and a rectifier 13 through which heating current is supplied tothe cathodes of the apparatus 1. Many details of the amplifying and detecting apparatus 4 have been omitted from the drawing for the reason that these details will be readily understood by those skilled in the art.

It will be apparent, for example, that the thermionic devices 5 to 11 each will be provided with a grid for controlling the transmission of current between its cathode and anode; that the grid circuit of the device 5 will be coupled to the tuned circuit through which signals are received; that these sig nals will be amplified and detected by the devices 5 to 11 which will be interconnected in the usual manner, and that the amplified 7:;

signals will be further amplified by the device 3 which is provided with an anode circuit coupled to the operating circuit of the sound producing device 1.

T 1e transformer 2 is provided with a primary circuit 1% adapted to be connected to a suitable source of current through a voltage control device shown as an :uljustable resistor 15 and with a plurality of secondary circuits 16 to 20. The circuits 16, 18 and 20 are; provided for supplying heating current tothe cathodes of devices 3, 12 and 13 respec tively. Current supplied through the winding); 17 is rectified by the rectifier 12 and is supplied to the anode circuits of devices 5 to 11 and 3 by connecting; the anode circuits to points of suitable potential in the impedance devices 21 and The anode circuit of the device 3 includes a resistor 23 shunted by a condenser 52% for the purpose of furnishing a negative bias for the grid of device 8.

A filter device comprising a reactor 25 and condensers 26 and 27 is provided for excluding the alternating component of the rectified 1953 current from the anode circuits of the thermionic devices. This filter device also affords a path for the audio frequency currents which a re produced in the anode circuit of device 3 due to the inductive coupling be tween this circuit and the last amplifying stage of the apparatus The operating circuit of the sound producing device 1 is coupled to the anode circuit of device 3 through means con'iprising a reactor 28 and a con denser 25). It will be observed that heating current is supplied to the cathodes of devices 5 to 11 through the rectifier 13, an impedance device shown as a resistor 80 and an ammeter 31, and that a filter device shown as reactors 32 and 3S and condensers 34, 35 and 36 are provided for excluding the alternating component of the rectified current from the cathode heating circuits. A condenser 87 is connected in parallel with the impedance device 21 for by-passing the high frequency current of the anode circuit of device 3. i

Fig. 2 shows an amplifying system which differs from that of Fig. 1 in that the rectifier is replaced by a rectifier 12 which is capable of rectifying only one-half of the alternating voltage wave applied to the circuit 17 the reactor 28 and condenser 29 are replaced by a transformer 38; and the sound producing device 1 is replaced by a sound producing device provided vith a core 39, an operating winding 40 and a field winding ll which is connected in series with the impedance device 30 and which is interconnected with condensers 42 to 4% and reactor 4-5 to form a filter whereby the alternating component of the rectified current is excluded from the cathode heating circuits of do 'iccs 5 to .11. It should be noted that the left hand end section 4L6 of the impedance device 30 provided for biasing the grid of device 5 to a negative potential.

The operation of the systems shown by Figs. 1 and 2 will be readily understood without detailed explanation. Signals received through an antenna and tuned circuit or other suitable apparatus are amplified and detected by the apparatus i and the.

thermionic amplifier 3 and these amplified sigi'ials are applied to the operating circuit of the sound producing device through the coupling interposed between the anode and operating circuits.

The embodiments of the invention illus trated and described herein have been selected for the purpose of clearly setting forth the principles involved. It will be apparent, however, that the invention is susceptible of being modified to meet the different conditions encountered in its use and I therefore aim to cover by the appended claims all modifications within the true spirit and scope of my invention.

\Vhat I claim as new and desire to secure by Letters Patent of the United States, is:

l. The combination with a multistage amplifying and detecting apparatus includinga plurality of thermionic devices each provided with a cathode and an anode, and a thermionic amplifier adapted to receive the amplified and detected output from said apparatus and having a cathode and an anode, of means for supplying operating direct current to said apparatus and to said amplifier, including a transformer provided with a primary circuit adapted to be connected to a source of alternating current, a plurality of secondary windings one of which is connected to the cathode of said thermionic amplifier, an impedance device to which the cathodes of said amplifying and detecting apparatus are connected, a second impedance device to which the anodes of said amplifying and detecting apparatus are connected, means providing a circuit between each of said impedance devices and one of said transformer windings, a filter device and a rectifier device interposed in each of said circuits in series relation to each other, and circuit means for supplying anode current to said amplifier device through the rectifier and filter devices associated with the second impedance device. 2. The combination with a multi-stage amplifying and detecting apparatus including a plurality of thermionic devices each provided with a cathode and an anode, and a thermionic amplifier adapted to IGCOlWE the amplified and detected output from said apparatus and having a cathode and an anode, of means for supplying operating direct current to said apparatus and to said amplifier, including a transformer provided with a primary circuit adapted to be connected to a source of alternating current, a plurality of secondary windings one of which is connected to the cathode of said thermionic amplifier, an impedance device to which the cathodes of said amplifying and detecting apparatus are connected, a second impedance device to which the anodes of said amplifying and detecting apparatus are connected, means providing a circuit between each of said impedance devices and one of said transformer windings, a filter device and a rectifier device interposed in each of said circuits in series relation to each other, a sound producing device having a field winding, and circuit connections between said field winding and the second impedance device whereby said field winding is included in said filter device.

In witness whereof, I have hereunto set my hand this 8th day of February, 1926.

FREDERICK C. BARTON. 

